Biohybrid microswimmers against bacterial infections

Abstract

Biohybrid microswimmers exploit the natural abilities of motile microorganisms e.g. in releasing cargo on-demand. However, using such engineered swarms to release antibiotics addressing bacterial infections has not yet been realized. Herein, a design strategy for biohybrid microswimmers is reported, which fea- tures the covalent attachment of antibiotics with a photo-cleavable linker to the algae C hlamydomonas reinhardtii via two synthetic steps. This surface engineering does not rely on genetic manipulations, pro- ceeds with high efficiency, and retains the viability or phototaxis of microalgae. Two different antibi- otics have been separately utilized, which result in activity against both gram-positive and gram-negative strains. Guiding the biohybrid microswimmers by an external beacon, and on-demand delivery of the drugs by light with high spatial and temporal control, allowed for strong inhibition of bacterial growth. This efficient strategy could potentially allow for the selective treatment of bacterial infections by engi- neered algal microrobots with high precision in space and time.